The present invention relates to doors. The invention particularly concerns safety catch arrangements, for vertically lifted doors, which operate to brake downward movement of a door panel, should a control cable loosen, break or should a similar catastrophic release occur.
In a variety of industries, building constructions with large doorways are used. The present disclosure concerns doorway openings in such constructions. As an example, a typical doorway opening in a building at a mining site will be characterized as background.
At a mining site, a doorway in a service building or other facility would need to be adequately large to handle very large mining equipment being moved into and out of the building. A typical such doorway would be, for example, 30-40 feet wide by 30-40 feet tall.
In general, such doorways are closed by door panels that are lifted upwardly (vertically) to selectively open the doorway. Typically such door panels are cable operated.
In typical large doors of the type characterized above, the movable door would generally comprise at least one and typically two or more panels, each panel being about 30-40 feet wide, by about 10-15 feet high. Each panel would typically weigh at least 100 lbs, often on the order of 1,000-3,000 lbs., and sometimes more, typically being constructed from structural steel framework elements covered by steel sheeting, for example 14 gauge steel sheeting. In some instances, the panels would be constructed in segments, secured together at the building construction site.
In order to accommodate an opening of 30-40 feet tall, typically the door would comprise 2-4 vertically movable segments, each of which extends completely, horizontally, across the doorway. For such arrangements, the panels would be positioned vertically offset from one another, when the door is closed.
Typically the panels are moved by a cable system using a counterweight system, so that all panels are moved at the same time, back-and-forth between lower (closed) and upper (open) positions. When in the upper position, the panels are typically aligned juxtaposed to one another, each maintained in a vertical orientation. In order to be aligned juxtaposed in the upper position, but positioned with one panel above the other when in a closed or lowered position, it is generally required that each panel be offset from the next adjacent panel. Thus, when the door is in the lowered position, although each panel (except for the bottom panel) is above a next lower panel, it is not directly above that panel, but rather it is above and either slightly behind or slightly in front of the next lower panel.
In general, it is desired to have safety catch systems to control downward movement of the panels, should a catastrophic failure in the system occur. The current disclosure concerns an advantageous safety catch arrangement, for such doors.
A safety catch assembly for selectively inhibiting downward movement of a door panel is provided. The preferred safety catch assembly in general comprises at least one, and typically first and second brake members positioned, when installed, to selectively move from a free position to a braking position. When in the braking position, each brake member engages a side portion of a rail. When two brake members are used, they are preferably positioned with braking forces generally in opposite directions, to brake the door panel. That is, in general, when two brake members are used, they are positioned to either: (a) apply the braking forces directed toward one another, i.e., with the braking force of one directed against the braking force of another; or, (b) to apply the braking forces with the braking force of one being applied in a direction approximately 180xc2x0 from the direction of the braking force of the other. The particular arrangement chosen, with respect to this, generally depends upon the nature of the rail.
Herein, when it is said that each brake member engages in a xe2x80x9crailxe2x80x9d reference is meant to a rail system on which the door panel is mounted, for vertical movement. When it said that a brake member engages a xe2x80x9csidexe2x80x9d or xe2x80x9cside portionxe2x80x9d of that rail, reference is meant to a side or side portion of the rail which extends generally parallel to a side of the door panel, as opposed to an edge or other surface of the rail which generally is directed toward an end of the door panel. Two particular arrangements of rails are described and shown in the figures below.
Herein, when reference is meant to a structure and its operation xe2x80x9cwhen installedxe2x80x9d it is meant when the safety catch assembly is operably assembled and installed in a door system, for operation. That is, the safety catch assembly is a component assembly mountable in or on a door panel in association with a vertical rail, for operation. Thus, when the equipment is characterized in terms of xe2x80x9cwhen installedxe2x80x9d it is meant when operably installed for proper function.
In general, the safety catch assembly includes an actuator assembly having a stay mechanism and a release mechanism: the stay mechanism maintaining the brake member(s) in the free or unlocked orientation or position (when installed) until failure of a lift mechanism for the panel; and, the release mechanism being constructed and arranged (when installed) to release the brake member(s) for movement into the braking orientation(s) or position(s), upon a selected or defined catastrophic failure of the lift mechanism.
The safety catch assembly also includes a biasing mechanism that biases the brake member(s) into the braking position(s), when the release mechanism is actuated to release the brake member(s) for movement into the braking position(s).
The assembly may, in some instances, be operated with a single rail side engaging brake member. However, in general two brake members will be preferred. In preferred constructions, the brake members are rotatable, between the free and braking orientations.
The present invention not only relates to preferred safety catch arrangements, but also to vertical lift door assemblies that include the safety catch assembly operably installed thereon; and, also, to methods of installation, assembly and braking.